I. Field of the Invention
This invention relates to a flow control cartridge which includes flow control valve plates manufactured of a hard, wear-resistant material, one of which is stationary and one movable, and, in particular, to a cartridge adapted to be received in the faucet valve body of a single-handle faucet which normally utilizes a ball-type valving member to regulate the mixing ratio and fluid flow rate from a pair of fluid sources to the faucet spout.
II. Description of the Prior Art
Single-handle mixer valves are widely utilized to regulate the mixing ratio between hot and cold water, flowing from separate pipes and delivered to a faucet, where the mixing is accomplished by a spherical or ball-type valving member. The spherical valving member is connected to a control lever and seated within a chamber of the faucet body. The valving member cooperates with a pair of tubular gasket seals seated in the inlet passageways of the valve body and urged against the spherical valving member by bias springs. The interior chamber of the faucet valve body includes a lower hemispherical portion, adapted to receive the spherical valving member, and an upper substantially cylindrical portion where a check halfbearing of the valving member is disposed. Extending from this interior chamber is an outlet passageway which communicates with the faucet spout. The control lever or handle for the valve extends out of the top of the valve body through an opening in the check halfbearing. This opening delimits the range the control lever may shift thereby limiting the rotational positions of the valving member from the full off position to positions providing the full flow of hot water or the full flow of cold water.
Although the ball-type mixer valves provide excellent performance, the valving members are subject to wear, particularly in hard water areas. The spherical form of the valving member prevents the use of control members made of hard, wear-resistant materials of the type used in flat control valve plates. Thus, the faucet valve will tend to leak after prolonged use.
Furthermore, in many cases it is necessary or convenient to construct a flow control cartridge having a compact form by reducing the overall dimensions to an absolute minimum. The known valve assemblies are incapable of reduction because the means for controlling the movement of the movable disk member or the spherical valving member includes an exterior swivel ring with a guide member and a slide bearing connected to the movable disk and guided by the swivel ring. Oftentimes, the extreme positions of the slide member, which carries the movable disk, are determined by the shape of the opening within which the control lever travels in order to limit the movement of the lever. However, any manufacturing tolerance or wear either in the connection between the control lever and slide member or between the control lever and the opening causes the movable plate to be inconsistently positioned when the lever abuts against the opening. As a result, large overlap areas must be provided between the cooperating parts of the plates in order to guarantee proper operation and proper closure. This increases the dimensional requirements of the assembly while limiting the surface area of the flow openings which determines the fluid flow rate through the cartridge. Moreover, by providing a shaped opening which defines the shiftings of the control lever, the overall size of the valve is not only increased but the range of movement for the lever is limited which may result in inaccurate flow regulation.